In mobile communications, multiple waves (multi-path) with different propagation delay time interfere one another due to variations in the lengths of transmission paths for respective receive waves of multiple wave propagation.
A CDMA (Code Division Multiple Access) receiver spreads information data over bands using a high-rate spread code with a cycle shorter than propagation time, and therefore, multiple waves which differ from each other in propagation delay time can be separated/extracted. Such CDMA receiver selects valid or available paths based on power delay profiles generated by despreading received signals while delaying the timing to carry out in-phase synthesis (rake synthesis), thereby achieving the diversity effect and improving receiving characteristics.
Besides, on the occasion of diversity handover (hereinafter referred to as DHO), the CDMA receiver receives signals (hereinafter referred to as branch) from a plurality of base stations, and selects available paths based on a delay profile of each received branch. The selected paths are subjected to rake synthesis.
There is found a technique concerning a multipath search method in Japanese Patent Application laid open No. HEI9-181704. On the other hand, Japanese Patent Application laid open No. 2002-141835 discloses a technique concerning a finger allocation method when there are plural branches.
The aforementioned conventional CDMA receiver, however, has to conduct a path search and store path information with respect to each branch at the time of DHO. Consequently, processing time is prolonged, and also more memory area is required to store the path information.